1. Field of the Invention
The present invention generally relates to packages for containing electronic devices, and more particularly to a package having a infrared sensor mounted to a silicon base through which infrared radiation passes before impinging the sensor.
2. Description of the Related Art
Infrared (IR) sensors have been used to measure the temperature of thermal sources, such as hot materials, humans, etc. To accurately detect heat radiated from a target, interference from ambient light, particularly visible light, should be filtered out. This can be done by adding a filter in front of the IR sensor. For example, in commonly-assigned U.S. Patent No. 6,844,606 to Logsdon et al., a chip formed of silicon—which allows only wavelengths longer than about 1.1 μm to pass through—is individually mounted to a chip carrier on which an infrared sensor is mounted so that the silicon chip is between the sensor and the target being sensed. In the automotive applications, an IR sensor package equipped with such a silicon “window” allows a targeted subject, such as the driver or passengers of a car, to be monitored with minimum background interferences.